"Where, then," asked Kennedy, "can photography be considered as
irrefutable evidence? The realism may convince all, except the
expert and the initiated after careful study. A shrewd judge will
be careful to insist that in every case the negative be submitted
and examined for possible alterations by a clever manipulator."

Kennedy bent his gaze on Dorgan. "Now, I do not accuse you, sir,
of anything. But a photograph has come into my possession in which
Mr. Carton is represented as standing in a group on a porch, with
Mr. Murtha, Mrs. Ogleby, and an unknown woman. The first three are
in poses that show the utmost friendliness. I do not hesitate to
say that was originally a photograph of yourself, Mr. Murtha, Mrs.
Ogleby, and a woman whom you know well. It is a pretty raw deal, a
fake in which Carton has been substituted by very excellent
photographic forgery."

"A fake--huh!" repeated Dorgan, contemptuously. "How about the
story of them? There's no negative. You've got to show me that the
original print stolen from Carton, we'll say, is a fake. You can't
do it. No, sir, those pictures were taken this summer."

Kennedy quietly laid down the bundle of photographs copied from
those alleged to have been stolen from Carton. He was pointing to
a shadow of a gable on the house.

"You see that shadow of the gable, Dorgan?" he asked. "Perhaps you
never heard of it, but it is possible to tell the exact time at
which a photograph was taken from a study of the shadows. It is
possible in theory and practice, and it can be trusted absolutely.
Almost any scientist, Dorgan, may be called in to bear testimony